An ongoing series of national surveys of youth is being carried out, involving the collection and reporting of data on an annual basis. As with other social reporting efforts, the study is envisioned as unending; however, for obvious practical reasons, the current program is limited to a five-year period. The basic sample for each data collection consists of the senior classes from about 130 high schools, selected to be nationally representative, and providing a total group of about 17,000 young men and women averaging 18 years of age. They receive paper and pencil questionnaires of about 45 minutes in length, group-administered in the schools under the supervision of staff members from the Institute for Social Research. Subsequently, subsamples of the 17,000 receive mailed follow-up questionnaires (N equals 7,000 per year per graduating class) during each of the following five years. The substance of the study is broad, but particularly emphasizes changes in drug behaviors and related attitudes, values, and aspirations. Among the purposes of the study are the following: (a) to systematically measure changes in drug use, patterns of use, drug attitudes, drug availability, and exposure to drug education, (b) to differentiate cohort (generational) changes from developmental and period effects, (c) to assess the changing impact of major social environments and roles, and (d) to assess the changing social meaning of drug use.